Pros & Cons of Television Essay Example for Free

Pros Cons of Television Essay For most people, watching television Is an enjoyable way to spend time. It Is an undemanding activity that passes the time and there are very few families that dont own at least one television. Since so many people now own a television, there has been a proliferation in the number of channels available and shows to watch, so that you can quite easily find yourself spending hours in front to the television. Consequently, you may neglect other activities that need doing. Thus, although television may help to ease boredom. Here are also some negative aspects associated with watching television. Breaking news shown live on your TV Global news network allows the latest global events to be aired worldwide and beamed directly to your living room. Examples (from top-left, clockwise) include September 1 lath attack, 2004 Tsunami in Indonesia, 2008 HINDI outbreak and 2011 earthquake In Japan. Pros of watching television The positive aspects of watching television include that you have something to talk to friends and relatives about. There are certain programs which are more popular than there and If you watch them you feel Included and that you have something In common with the people around you. Television can help to foster a sense of national identity, since a significant proportion of the population will be exposed to the same kinds of news programs and television shows, so that people feel that they belong to a wider community. Plus, television can also be Informative and educational, opening peoples eyes up to the world outside. Educational TV programs Educational TV programs provide priceless information that not only educate but also pens up your mind. Most of these programs teach and educate people on subjects that you may otherwise will not know and are never taught in schools. Non-educational TV programs However, there are also a lot of television shows that are not very educational, and could even be considered trash. Reality shows, for Instance, offer nothing of any worth to the audience. Yet people still tune in. People get hooked on shows which are poorly produced and concentrate mostly on issues of sex and violence. Although here is no conclusive evidence that watching violence on television makes children tofu people would become desensitizing to it, and that this could make it easier for children to engage in violent activities. Watching too much TV can lead to weight gain, poor social skills and lower academic results Unsupervised children spending too much of their time in front of a TV can have a big impact on their life. Obesity, lack of social skills and poor academic results are Just some of the effects TV have on children. Some psychologist believe that too such TV time can have a major effect in the psychology of the child. Children are suppose to interact and play, not sit and watch. Poor parenting and weight gain It is also evident that many people spend too much time watching television, so that parents dont bother to spend any time playing or talking with their children. It is far easier to stick them in front of the television, rather than taking them to the park. It cant be a coincidence that so many people are now overweight when they spend much more time watching television than they would have done years ago. People seed to be a lot more active, but now television is the most convenient way for individuals to keep themselves occupied. Thus, they burn hardly any calories while most probably consuming an excessive amount of calories. Its addictive Even though there are many negative aspects associated with watching television, many people enjoy television far too much to reduce the amount they watch or to avoid watching television altogether. People enjoy not having to think for themselves and to be able to sit down and watch something that helps them to relax, so why would they change?

Digital modulation and demodulation

Digital modulation and demodulation Chapter 1 Digital Communications 1.0 Digital Communication 1.1 Introduction Communication Process: When we think of communication, we usually think of people talking or listening to each other. This may happen face to face, or it may occur through the assistance of a telephone, radio, or television. Basically, communication is the transfer of information. Life In our modern, complex world depends more and more on the transfer of information. The increasing dependency on the transfer of information has stimulated the growth of more and more communication systems. This surge in communication and communication systems has been referred to as a technological revolution. This shows understand the transfer of information in a communication system The communication system will consist of at least the three parts shown. The channel can be as simple as the air that carries the sound of your voice, or as complex as the satellite network required to carry a television program around the world. The most common problem encountered by the communication process is interference. Interference is any force that disrupts or distorts the information or message while it is being channeled. It could be noise, as in the case of normal conversation, or atmospheric weather changes, as In the case of radio or television The biggest cause of interference, however, is a simple misinterpretation of the intended message. Cultural, economic, and political diversities allow people to receive the same message but interpret it differently. Communication Systems: Communication system is a combination of processes and hardware used to accomplish the transfer of Information (communication). A system is a group of interrelated parts. We find that there are systems all around us. In nature, we can also find examples of systems that have been created by people. An automobile, a washing machine, and an electric drill are examples. 1.2 TYPES OF COMMUNICATION: Based on the requirements, the communications can be of different types: Point-to-point communication: In this type, communication takes place between two end points. For instance, in the case of voice communication using telephones, there is one calling party and one called party. Hence the communication is point-to-point. Point-to-multipoint communication: In this type of communication, there is one sender and multiple recipients. For example, in voice conferencing, one person will be talking but many others can listen. The message from the sender has to be multicast to many others. Broadcasting: In a broadcasting system, there is a central location from which information is sent to many recipients, as in the case of audio or video broadcasting. In a broadcasting system, the listeners are passive, and there is no reverse communication path. In simplex communication, the communication is one-way only. In half-duplex communication, communication is both ways, but only in one direction at a time. In full-duplex communication, communication is in both directions simultaneously. Simplex communication: In simplex communication, communication is possible only in one direction. There is one sender and one receiver; the sender and receiver cannot change roles. Half-duplex communication: Half-duplex communication is possible in both directions between two entities (computers or persons), but one at a time. A walkie-talkie uses this approach. The person who wants to talk presses a talk button on his handset to start talking, and the other persons handset will be in receiving mode. When the sender finishes, he terminates it with an over message. The other person can press the talk button and start talking. These types of systems require limited channel bandwidth, so they are low cost systems. Full-duplex communication: In a full-duplex communication system, the two parties-the caller and the called-can communicate simultaneously, as in a telephone system. However, note that the communication system allows simultaneous transmission of data, but when two persons talk simultaneously, there is no effective communication! The ability of the communication system to transport data in both directions defines the system as full-duplex. 1.3 ANALOG VERSUS DIGITAL TRANSMISSION: In analog communication, the signal, whose amplitude varies continuously, is transmitted over the medium. Reproducing the analog signal at the receiving end is very difficult due to transmission impairments. Hence, analog communication systems are badly affected by noise. In a digital communication system, 1s and 0s are transmitted as voltage pulses. So, even if the pulse is distorted due to noise, it is not very difficult to detect the pulses at the receiving end. Hence, digital communication is much more immune to noise as compared to analog communication. 1.4 Digital Modulation: Firstly, what do we mean by digital modulation? Typically the objective of a digital communication system is to transport digital data between two or more nodes. In radio communications this is usually achieved by adjusting a physical characteristic of a sinusoidal carrier, the frequency, phase, amplitude or a combination thereof. This is performed in real systems with a modulator at the transmitting end to impose the physical change to the carrier and a demodulator at the receiving end to detect the resultant modulation on reception. * Modulation is the process of varying some characteristic of a periodic wave with an external signal. * Modulation is utilized to send an information bearing signal over long distances. * Radio communication superimposes this information bearing signal onto a carrier signal. * These high frequency carrier signals can be transmitted over the air easily and are capable of traveling long distances. * The characteristics (amplitude, frequency, or phase) of the carrier signal are varied in accordance with the information bearing signal. * In the field of communication engineering, the information bearing signal is also known as the modulating signal. * The modulating signal is a slowly varying signal as opposed to the rapidly varying carrier frequency. The principal of a digital communication system is that during a finite interval of time, it sends a waveform from a finite set of possible waveforms, in contrast to an analog communication system, which sends a waveform from an infinite variety of waveform shapes, with theoretically infinite resolution. In a DCS (digital communication system), the objective of the receiver is not to reproduce a transmitted waveform with precision. The objective is to determine from a noise-perturbed signal which waveform from the finite set of waveforms was sent by the transmitter. Why Digital?  · The primary advantage is the ease with which digital signals, compared with analog signals, is regenerated. The shape of the waveform is affected by two basic mechanisms. As all transmission lines and circuits have some non-ideal frequency transfer function, there is a distorting effect on the ideal pulse. Unwanted electrical noise or other interference further distorts the pulse waveform. Both of these mechanisms cause the pulse shape to degrade. * With digital techniques, extremely low error rates producing high signal fidelity are possible through error detection and correction but similar procedures are not available with analog. * Digital circuits are more reliable and can be reproduced at a lower cost than analog circuits. * Digital hardware lends itself to more flexible implementation than analog circuits. * The combination of digital signals using Time Division Multiplexing (TDM) is simpler than combining analog signals using Frequency Division Multiplexing (FDM). Metrics for Digital Modulation à ¢Ã¢â€š ¬Ã‚ ¢ Power Efficiency Ability of a modulation technique to preserve the fidelity of the digital message at low power levels Designer can increase noise immunity by increasing signal power Power efficiency is a measure of how much signal power should be increased to achieve a particular BER for a given modulation scheme Signal energy per bit / noise power spectral density: Eb / N0 à ¢Ã¢â€š ¬Ã‚ ¢ Bandwidth Efficiency Ability to accommodate data within a limited bandwidth Tradeoff between data rate and pulse width Throughput data rate per hertz: R/B bps per Hz à ¢Ã¢â€š ¬Ã‚ ¢ Shannon Limit: Channel capacity / bandwidth C/B = log2(1 + S/N) Disadvantages of Digital Systems * Digital systems tend to be very signal processing intensive compared with analog. * Digital systems need to allocate a significant share of their resources to the task of synchronization at various levels. With analog signals synchronization is accomplished more easily. * One disadvantage of digital communication system is non-graceful degradation. When the SNR drops below a certain threshold, the quality of service can change form very good to very poor. Most analog systems degrade more gracefully. Formatting The goal of the first essential processing step, formatting is to ensure that the source signal is compatible with digital processing. Transmit formatting is a transformation from source information to digital symbols. When data compression in addition to formatting is employed, the process is termed source coding. The digital messages are considered to be in the logical format of binary 1s and 0s until they are transformed by pulse modulation into base band (pulse) waveforms. Such waveforms are then transmitted over a cable. No channel can be used for the transmission of binary digits without first transforming the digits to waveforms that are compatible with the channel. For base band channels, compatible waveforms are pulses. The conversion from a bit of streams to a sequence of pulse waveforms takes place in the block labeled, modulator. The output of a modulator is typically a sequence of pulses with characteristics that correspond to the digits being sent. After transmission through the channel the pulse waveforms are recovered (demodulated) and detected to produce an estimate of the transmitted digits. Formatting in a digital Communication System Symbols When digitally transmitted, the characters are first encoded into a sequence of bits, called a bit stream or base band signal. Group of K bits can then be combined to form new digits, or symbols, from a finite or alphabet of M = 2^K such symbols. A system using a symbol set size of M is referred to as M-array system. Waveform Representation of Binary Digits Digits are just abstractions way to describe the message information. Thus we need something physical that will represent or carry the digits. Thus binary digits are represented with electrical pulses in order to transmit them through a base band channel. At the receiver, a determination must be made regarding the shape of pulse. The likelihood of correctly detecting the pulse is a function of the received signal energy (or area under the pulse). PCM Waveform Types When pulse modulation is applied to a binary symbol, the resulting binary waveform is called a PCM waveform. There are several types of PCM waveforms. These waveforms are often called line codes. When pulse modulation is applied to non-binary symbol, the resulting waveform is called an M-ary pulse modulation waveform. The PCM waveforms fall into the following four groups. 1) Non return to zero (NRZ) 2) Return to zero (RZ) 3) Phase encoded ) Multilevel binary The NRZ group is probably the most commonly used PCM waveform. In choosing a waveform for a particular application, some of the parameters worth examining are 1) DC component 2) Self clocking 3) Error detection ) Bandwidth compression 5) Differential encoding 6) Noise immunity The most common criteria used for comparing PCM waveforms and for selecting one waveform type from many available are 1) Spectral characteristics 2) Bit synchronization capabilities 3) Error detection capabilities ) Interference 5) Noise immunity 6) Cost and complexity of implementation Bits per PCM Word and Bits per Symbol Each analog sample is transformed into a PCM word up to group of bits. The number of quantization levels allowed for each sample can describe the PCM word size; this is identical to the number of values that the PCM word can assume. We use L=2^l Where L is the number of quantization levels in PCM word, l is the number of bits needed to represent those levels. M-ARY Pulse Modulation Waveforms There are three basic ways to modulate information onto a sequence of pulses; we can vary the pulses amplitude, position, or duration. This leads to the names 1) PAM (pulse amplitude modulation) 2) PPM (pulse position modulation) 3) PDM/PWM (pulse duration modulation/ pulse width modulation) When information samples without any quantization are modulated on to the pulses, the resulting pulse modulation can be called analog pulse modulation. When the information samples are first quantized, yielding symbols from an M-ary alphabet set, and the modulation on to pulses, the resulting pulse modulation is digital and we refer to it as M-ary pulse modulation. Base-band modulation with pulses has analogous counterparts in the area of band-pass modulation. PAM is similar to amplitude modulation, while PPM and PDM are similar to phase and frequency modulation respectively. Spectral Density The spectral density of a signal characterizes the distribution of the signals energy or power in the frequency domain. Energy Spectral Density We can relate the energy of a signal expressed in time domain to the energy expressed in frequency domain as: à ¢Ã‹â€ Ã… ¾ Ex = à ¢Ã‹â€ Ã‚ « x ²(t) dt -à ¢Ã‹â€ Ã… ¾ à ¢Ã‹â€ Ã… ¾ = à ¢Ã‹â€ Ã‚ « |X (f) | ² df -à ¢Ã‹â€ Ã… ¾ Where X (f) is the Fourier transform of the non periodic signal x (t). Let à Ã‹â€  (t) = |X (f) | ² à ¢Ã‹â€ Ã… ¾ Ex = 2 à ¢Ã‹â€ Ã‚ « à Ã‹â€ x (f) df -à ¢Ã‹â€ Ã… ¾ Power Spectral Density The power spectral density function Gx (t) of the periodic signal x (t) is real, even and nonnegative function of frequency that gives the distribution of the power of x (t) in the frequency domain. à ¢Ã‹â€ Ã… ¾ Gx (t) = à ¢Ã‹â€ Ã¢â‚¬Ëœ |Cn| ² à ¢Ã‹â€ Ã‚ «(f-nfo) n =-à ¢Ã‹â€ Ã… ¾ PSD of a periodic signal is a discrete function of frequency. à ¢Ã‹â€ Ã… ¾ Px = à ¢Ã‹â€ Ã‚ « Gx (t) df -à ¢Ã‹â€ Ã… ¾ à ¢Ã‹â€ Ã… ¾ = 2 à ¢Ã‹â€ Ã‚ «Gx (F) df 0 If x (t) is a non-periodic signal it cannot be expressed by a Fourier series, and if it is a non-periodic power signal (having infinite energy) it may not have a Fourier transform. However we still express the PSD of such signals in a limiting sense. Chapter 2 Modulation and Demodulation 2.0 Modulation and Demodulation Since the early days of electronics, as advances in technology were taking place, the boundaries of both local and global communication began eroding, resulting in a world that is smaller and hence more easily accessible for the sharing of knowledge and information. The pioneering work by Bell and Marconi formed the cornerstone of the information age that exists today and paved the way for the future of telecommunications. Traditionally, local communication was done over wires, as this presented a cost-effective way of ensuring a reliable transfer of information. For long-distance communications, transmission of information over radio waves was needed. Although this was convenient from a hardware standpoint, radio-waves transmission raised doubts over the corruption of the information and was often dependent on high-power transmitters to overcome weather conditions, large buildings, and interference from other sources of electromagnetic. The various modulation techniques offered different solutions in terms of cost-effectiveness and quality of received signals but until recently were still largely analog. Frequency modulation and phase modulation presented certain immunity to noise, whereas amplitude modulation was simpler to demodulate. However, more recently with the advent of low-cost microcontrollers and the introduction of domestic mobile telephones and satellite communications, digital modulation has gained in popularity. With digital modulation techniques come all the advantages that traditional microprocessor circuits have over their analog counterparts. Any shortfalls in the communications link can be eradicated using software. Information can now be encrypted, error correction can ensure more confidence in received data, and the use of DSP can reduce the limited bandwidth allocated to each service. As with traditional analog systems, digital modulation can use amplitude, frequency, or phase modulation with different advantages. As frequency and phase modulation techniques offer more immunity to noise, they are the preferred scheme for the majority of services in use today and will be discussed in detail below 2.1 Digital Frequency Modulation: A simple variation from traditional analog frequency modulation can be implemented by applying a digital signal to the modulation input. Thus, the output takes the form of a sine wave at two distinct frequencies. To demodulate this waveform, it is a simple matter of passing the signal through two filters and translating the resultant back into logic levels. Traditionally, this form of modulation has been called frequency-shift keying (FSK). 2.2 Digital Phase Modulation: Spectrally, digital phase modulation, or phase-shift keying, is very similar to frequency modulation. It involves changing the phase of the transmitted waveform instead of the frequency, these finite phase changes representing digital data. In its simplest form, a phase-modulated waveform can be generated by using the digital data to switch between two signals of equal frequency but opposing phase. If the resultant waveform is multiplied by a sine wave of equal frequency, two components are generated: one cosine waveform of double the received frequency and one frequency-independent term whose amplitude is proportional to the cosine of the phase shift. Thus, filtering out the higher-frequency term yields the original modulating data prior to transmission. * Modulate and demodulate/detect blocks together are called a modem. * The frequency down conversion is performed in the front end of the demodulator. * Only formatting, modulation, demodulation/detection and synchronization are essential for a digital communication system. * FORMATTING transforms the source information into bits. * From this point up to pulse modulation block, the information remains in the form of a bit stream. * Modulation is the process by which message symbols or channel symbols are converted to waveforms that are compatible with the requirements imposed by transmission channel. Pulse modulation is an essential step because each symbol to be transmitted must first be transformed from a binary representation to a base band waveform. * When pulse modulation is applied to binary symbols, the resulting binary waveform is called a PCM waveform. When pulse modulation is applied to non-binary symbols, the resulting waveform is called an M-ary pulse modulation waveform. * Band pass modulation is required whenever the transmission medium will not support the propagation of pulse like waveforms. * The term band pass is used to indicate that the base band waveform gi (t) is frequency translated by a carrier wave to a frequency that is much larger than the spectral content of gi (t). * Equalization can be described as a filtering option that is used in or after the demodulator to reserve any degrading effects on the signal that were caused by the channel. An equalizer is implemented to compensate for any signal distortion caused by a no ideal hi(t) * Demodulation is defined as a recovery of a waveform (band pass pulse) and detection is defined as decision-making regarding the digital meaning of that waveform. 2.3 Linear Modulation Techniques * Digital modulation techniques may be broadly classified as linear and non-linear. In linear modulation techniques, the amplitude to the modulation signal S (t) varies linearly with the modulating digital signal m (t). * Linear modulation techniques are bandwidth efficient. * In a linear modulation technique, the transmitted signal S (t) can be expressed as: S (t) = Re [Am (t) exp (j2pfct)] = A [mr(t)cos(2pfct) mI(t)sin(2pfct)] Where A is the amplitude fc is the carrier frequency m (t) = mr(t) + mI(t) is a complex envelope representation of the modulated signal which is in general complex form. * From the equations above, it is clear that the amplitude of the carrier varies linearly with the modulating signal. * Linear modulation schemes, in general do not have a constant envelope. Linear modulation schemes have very good spectral efficiency. Normalized Radian Frequency Sinusoidal waveforms are of the form: X (t) =Acos (wt+f) - (1) If we sample this waveform, we obtain X[n] =x (nTs) =Acos (wnTs+f) =Acos (wn+f) (2) Where we have defined w to be Normalized Radian Frequency: w=wTs The Signal in (2) is a discrete time cosine signal, and w is the discrete time radian frequency. w has been normalized by the sampling period. w has the units of radians/second, w=wTs has the units of radians; i.e. wis a dimensionless quantity. This is entirely consistent with the fact that the index n in x[n] is a dimensionless. Once the samples are taken from x (t), the time scale information is lost. The discrete time signal is just a sequence of numbers, and these numbers carry no information about the sampling period, which is the information required to reconstruct the time scale. Thus an infinite number of continuous time sinusoidal signals can be transformed into the same discrete time sinusoid by sampling. All we need to is to change the sampling period with changes in frequency of the continuous time sinusoid. 2.4 Baseband Transmission Baseband Demodulation/Detection  · The filtering at the transmitter and the channel typically cause the received pulse sequence to suffer from ISI (Inter Symbol Interference), thus the signal is not quiet ready for sampling and detection.  · The goal of the demodulator is to recover the pulse with best possible signal to noise ratio (SNR), free of any ISI.  · Equalization is a technique used to help accomplish this goal. Every type of communication channel does not require the equalization process. However equalization process embodies a sophisticated set of signal processing techniques, making it possible to compensate for channel induced interference.  · A received band pass waveform is first transformed to a base band waveform before the final detection step takes place.  · For liner systems, the mathematics of detection is unaffected by a shift in frequency. * According to the equivalence theorem, all linear signal-processing simulations can take place at base band (which is preferred for simplicity) with the same result as at band pass. Thus the performance of most digital communication systems will often be described and analyzed as if the transmission channel is a base band channel. Chapter 3 p/4 Quadrature 3.0 p/4 Quadrature Phase Shift Keying (p/4 QPSK) 3.1 Linear Modulation Techniques * Digital modulation techniques may be broadly classified as linear and non-linear. In linear modulation techniques, the amplitude to the modulation signal S (t) varies linearly with the modulating digital signal m (t). * Linear modulation techniques are bandwidth efficient. * In a linear modulation technique, the transmitted signal S (t) can be expressed as: S (t) = Re [Am (t) exp (j2pfct)] = A [mr(t)cos(2pfct) mI(t)sin(2pfct)] Where A is the amplitude fc is the carrier frequency m (t) = mr(t) + mI(t) is a complex envelope representation of the modulated signal which is in general complex form. * From the equations above, it is clear that the amplitude of the carrier varies linearly with the modulating signal. * Linear modulation schemes, in general do not have a constant envelope. Linear modulation schemes have very good spectral efficiency. There are three major classes of digital modulation techniques used for transmission of digitally represented data: * Amplitude-shift keying (ASK) * Frequency-shift keying (FSK) * Phase-shift keying (PSK) All convey data by changing some aspect of a base signal, the carrier wave, (usually a sinusoid) in response to a data signal. In the case of PSK, the phase is changed to represent the data signal. There are two fundamental ways of utilizing the phase of a signal in this way: * By viewing the phase itself as conveying the information, in which case the demodulator must have a reference signal to compare the received signals phase against; or * By viewing the change in the phase as conveying information differential schemes, some of which do not need a reference carrier (to a certain extent). A convenient way to represent PSK schemes is on a constellation diagram. This shows the points in the Argand plane where, in this context, the real and imaginary axes are termed the in-phase and quadrature axes respectively due to their 90 ° separation. Such a representation on perpendicular axes lends itself to straightforward implementation. The amplitude of each point along the in-phase axis is used to modulate a cosine (or sine) wave and the amplitude along the quadrature axis to modulate a sine (or cosine) wave. In PSK, the constellation points chosen are usually positioned with uniform angular spacing around a circle. This gives maximum phase-separation between adjacent points and thus the best immunity to corruption. They are positioned on a circle so that they can all be transmitted with the same energy. In this way, the moduli of the complex numbers they represent will be the same and thus so will the amplitudes needed for the cosine and sine waves. Two common examples are binary phase-shift keying (BPSK) which uses two phases, and quadrature phase-shift keying (QPSK) which uses four phases, although any number of phases may be used. Since the data to be conveyed are usually binary, the PSK scheme is usually designed with the number of constellation points being a power of 2. 3.2 Amplitude Shift Keying (ASK) Amplitude shift keying ASK in the context of digital communications is a modulation process, which imparts to a sinusoid two or more discrete amplitude levels. These are related to the number of levels adopted by the digital message. For a binary message sequence there are two levels, one of which is typically zero. Thus the modulated waveform consists of bursts of a sinusoid. In Amplitude Shift Keying the Amplitude varies whereas the phase and frequency remains the same as shown in following . One of the disadvantages of ASK, compared with FSK and PSK, for example, is that it has not got a constant envelope. This makes its processing (eg, power amplification) more difficult, since linearity becomes an important factor. However, it does make for ease of demodulation with an envelope detector. Thus demodulation is a two-stage process: à ¥ Recovery of the band limited bit stream à ¥ Regeneration of the binary bit stream 3.3 Frequency-shift keying (FSK) Frequency-shift keying (FSK) is a method of transmitting digital signals. The two binary states, logic 0 (low) and 1 (high), are each represented by an analog waveform. Logic 0 is represented by a wave at a specific frequency, and logic 1 is represented by a wave at a different frequency. In frequency Shift Keying the frequency varies whereas the phase and amplitude remains the same. Phase shift keying (PSK) Phase Shift Keying (PSK) was developed during the early days of the deep-space program. PSK is now widely used in both military and commercial communication systems. In phase shift Keying the phase of the transmitted signal varies whereas the amplitude and frequency remains the same. The general expression for the PSK is as Where, ji(t) = the phase term will have M discrete values, given by, ji(t) = 2pi /M 3.4 Binary PSK In binary phase shift keying we have two bits represented by the following waveforms; S0(t) = A cos (wt) represents binary 0 S1(t) = A cos (wt + p) represents binary 1 For M-array PSK, M different phases are required, and every n (where M=2n) bits of the binary bit stream are coded as one signal that is transmitted as A sin (wt + qj) where j=1,.., M 3.5 Quadra phase-Shift Modulation Taking the above concept of PSK a stage further, it can be assumed that the number of phase shifts is not limited to only two states. The transmitted carrier can undergo any number of phase changes and, by multiplying the received signal by a sine wave of equal frequency, will demodulate the phase shifts into frequency-independent voltage levels. This is indeed the case in quadraphase-shift keying (QPSK). With QPSK, the carrier undergoes four changes in phase (four symbols) and can thus represent 2 binary bits of data per symbol. Although this may seem insignificant initially, a modulation scheme has now been supposed that enables a carrier to transmit 2 bits of information instead of 1, thus effectively doubling the bandwidth of the carrier Eulers relations state the following: Now consider multiplying two sine waves together, thus From Equation 1, it can be seen that multiplying two sine waves together (one sine being the incoming signal, the other being the local oscillator at the receiver mixer) results in an output frequency double that of the input (at half the amplitude) superimposed on a dc offset of half the input amplitude. Similarly, multiplying by gives which gives an output frequency double that of the input, with no dc offset. It is now fair to make the assumption that multiplying by any phase-shifted sine wave yields a demodulated waveform with an output frequency double that of the input frequency, wh

Education for citizenship is important because every society needs Essa

Education for citizenship is important because every society needs people to contribute effectively, in a variety of ways, to the future health and wellbeing of communities and the environment, locally, nationally and globally. Rationale for citizenship Education for citizenship is important because every society needs people to contribute effectively, in a variety of ways, to the future health and wellbeing of communities and the environment, locally, nationally and globally. Fostering active and responsible citizens contributes to the process of developing a healthy and vibrant culture of democratic participation. Whilst all individuals share the rights and responsibilities of citizenship, regardless of status, knowledge or skill, it is clear that citizenship may be exercised with different degrees of effectiveness. The opportunities for learning that are provided in primary education make important contributions to the process of educating for active and responsible citizenship. At the same time, the contributions of formal education need to be seen alongside, and in interaction with, parents, carers and the media and opportunities for community-based learning. Also, primary schools need to take account of the diversity of the local communities in which young people live. Aims of the topic The rights and responsibilities of citizens are reciprocal in many respects. If we all have a right to be treated with respect, then it follows that we have a clear obligation to treat all others with respect. If we all have a right to a say on matters that affect our lives, then we have a responsibility to attend to the views of others on matters that also affect them. However, it is also clear that per... ...rnes. Holden, C. (2003) Citizenship in the Primary school: Going Beyond Circle Time. Pastoral care in Education, 21 (3),24-29 Kerr, David.(1998). Citizenship education in primary schools : a national survey commissioned by the Institute for Citizenship Studies about opportunities for citizenship education and community involvement in primary schools, final report . QCA Klein, Reva . (2001) Citizens by right : citizenship education in primary schools : Stoke-on-Trent : Trentham and Save the Children. Lister, I. (1984) Teaching and learning about human rights. Strasbourg: Council of Europe. Starkey, H. (1992) Back to Basic Values: Education for justice and peace in the world, Journal of Moral Education, 21(3), 195-92 United Nations.(1989) Teaching human rights : practical activities for primary and secondary schools. New York : United Nations.

Monetary Policy Essay -- Expansionary and Contractionary Policy

Introduction Monetary policy is among the many tools used by a national government to manipulate its financial system. Monetary policy refers to the method used by the financial authority of any country to control the supply and availability of money (Woelfel, 1994). It is often targeted at interest rates to achieve lay down objectives directed towards economic growth and stability (Woelfel, 1994). Monetary policy rests on the link between interest rates in an economy, that is, the relationship between interest rates and the total money supply. It employs a variety of methods to control outcomes like inflation, economic growth, currency exchange rates and unemployment. Monetary policy can either be expansionary policy in which case there is a rapid increase in the total money in circulation in the economy, or contractionary policy in which case there is a slow increase or decrease in the total amount of money in circulation in the economy (Woelfel, 1994). The description of monetary policy takes the following approach; accommodative if the intention of the set interest rates is to stimulate economic growth, neutral if the intention is neither to fight inflation nor to stimulate economic growth and tight if the intention is to decrease inflation (Woelfel, 1994). These can be achieved through various tools including raising reserve requirements, increasing interest rates by fiat, and decreasing the monetary base, depending on the intended results (Woelfel, 1994). Monetary policy is always intended to either increase or decrease the amount of money in circulation in the economy. Reducing interest rates encourages borrowing thus increases the amount of money in circulation. It is however challenging when the interest rates are... ...ood of increased tax on their savings (Goodfriend, 2000). It is therefore fundamental for central banks to promise the public that it will maintain some elements of quantitative easing even as the economy recovers in order to gain public trust. Besides adjustments on tax and expenditure instruments takes a longer period thus may only be effective in neutralizing the zero bound in the long run but not short term effect as required in this case. The signaling Channel This channel unlike the others capitalizes on shaping the publics expectations through visible signal about central bank’s future policy intentions. This channel is more of a visible sign for central governments commitment to maintain zero policy rates for longer duration. This channel requires central banks to show a remarkable willingness to break from the previous conventional monetary policies.

Leading Edge :: essays research papers fc

The Leading Edge Management in organizations today are trying to capture both quality and productivity (bottom line results) from their employees, and are spending millions of dollars in time, capital, and human resources. However, without the proper paradigm shift in leadership roles, which must include a new appreciation on the importance of principled centered leadership that recognizes that people are the highest value in any organization, the investment no matter how great will not accomplish their goals. Managers today have to become more effective in leading and managing their employees. They have to start with a new mind set, change their frame of reference, change how they see the world, how they think about people, and how they view management and leadership. This will bring about quantum improvements in their organization. (Covey) Today's authoritarian style puts managers at a higher level of importance than that of his employees, he makes the decision, gives the commands, and workers conf orm and cooperate, perform and contribute as requested to receive the rewards of pay and other benefits. When managers accept that the "old way" of doing things is not fundamentally the right way, and they shift to a new style that puts principle-centered leadership first, a unique relationship will develop. They will see that people have more creative energy, resourcefulness, and initiative to contribute when they feel valued and their accomplishments are valued. When managers begin to work with the whole person and embrace principles of fairness and kindness and make better use of their talents, than people have a sense of doing something that matters, something with meaning. (Covey) In my organization we are fast paced and deadline driven, each of us has to train and depend on our employees decision making process. I know which of my employees can handle which tasks and set goals for each according to their abilities. I usually get them together in a group to discuss wh at our immediate objectives are. I encourage input from every level, including our part time employees, so everyone feels included and when we achieve goals, everyone wins. We monitor our progress, and meet frequently if a problem arises, and are very quick to praise each other when we have moved closer to our goals. I feel including everyone in this process gives everyone a sense of ownership in the organization. My employees want to contribute, they take great pride in helping in the decision making process, their sense of meaning and worth are just as great a reward as any paycheck could be.

Differences between family and friends Essay

Throughout our lives we interact in many and varied relationships. These can range from intense emotional and physical interactions, to casual acquaintances. Our ability to bond, congregate and network within these relationships is not restricted to the family or kin from whom we are born; many are the result of friendships formed within our societal settings. We develop friendship relationships within the work place, sporting activities and shared community interests. The commonality of interest can be in residential status, class, race, gender and religious beliefs. The formation of relationships can have a multitude of meanings and importance to the individual, whether formed with family or friends. So how do the importance of relationships between family and friends differ? According to Baker (2001, p.1) â€Å"Our ‘personal’ decisions and lifestyle ‘choices’ are influenced in a myriad, often hidden, ways by what happens in the wider world†. This suggests that as individuals we need the influence of the outside world to assist in our decision-making processes. However, both family and friendship relationships offer a range of external (social) and internal (private) life networks from which the individual or group can access personal and social knowledge, resources and support. The difference in the level, mannerism and depth of needs attended to by both family and friendship relationships must then be discussed to access the importance of each and the role it plays in the life of the individual and society. Friendship Goerg Simmel (in G. Little, 1993, p.31) saw friendship as pure sociability. Simmell â€Å"pictured society as a web of sociability, a subtle balance of delicate exchanges† †¦ â€Å"it was only the name given to the comings and going of human beings, the interchanges that simultaneously link and separate people†. Simmel further describes friends as artists, claiming â€Å"friends must  commit themselves to communicating well, putting all distraction aside†. Simmell’s description of friendship in society, describes the way in which we communicate in our external lives, separate to that of family or kin relations. The communicative commitment we put into these meetings will depend on the level of interaction desired, given our commonality and interest. Therefore, the formation of friendships is based on the attention given to conversation, how well we communicate and the manner in which we construct our communication. All other encounters are purely polite exchanges of greetings between people we meet externally. Friendly interactions can therefore become an extension of our internal family lives. A case study of social networks conducted by Lyn Richards (in Gilding, 1999, p.121-23) of a Melbourne suburb revealed how â€Å"residents constructed a wide variety of relationships with their neighbours†. The social exchange of neighbourhood residents extended to sharing equipment and getting to know each other on a more personal basis, allowing friendship relations to enter the internal domain family life by choice rather than necessity. This offers an interesting perspective to Simmell’s analysis of friendship simply being polite but attentive exchanges of our everyday external lives. It suggests that we not only form friendships externally out of politeness but also  internally to share our family relations. Richards noted however, that the association between friends and family relations are separated by the difference in time spent with family and friends. Edward Shorter (1979, p.231) writes†¦Ã¢â‚¬ in traditional society the kin group counted for relatively little in emotional terms, being primarily a reservoir of material support in emergencies†. The view here is that friendship relations are an extension of family relations, allowing additional resources to be obtained. Friendship is then seen as an important  commodity to completing our hierarchy of needs. Therefore, placing restrictions on the importance and position of family and friendship contributing factors to our family and societal needs, with the extent of these needs measured in material and emotional contexts. Demographically family structures have endured many changes to the way in which family member conduct their lives. Changes to labour market forces, socio-economics and lifestyle choices, have left many with little or no time to conduct friendship relationships within the family unit. The importance of emotional support and mental well-being is then passed onto external avenues such as social services and friendship alliances. Meaning, that whilst our physical needs are being met through income support (wages, benefits), our emotional needs are neglected over time taken to achieve our physical and material needs. Therefore, positioning friendship relations as an important aspect of our familial and societal structure. Talcott Parsons (in van Krieken et al, 2000, p.328) described the functions of the nuclear family as the â€Å"primary socialization of children and the stabilization of the adult personalities of the population of society (1955a, p.16). Parsons analysis of  socialisation and stabilisation functioning describes the family as a secure and sociable entity, capable of providing both social learning and emotional well-being. To support Parsons description Bell and Zajdow (in Jureidini and Poole, 2003, p.275-76) describe the family â€Å"as an entity where people have their emotional needs cared for by a wife or mother has displaced the household whose primary purpose was to produce goods for the material well-being of family members†. The descriptions of families given here, lead to families providing emotional support for its members, similar to that of friendship relationships. How can we determine at this point, which is more important? Family support and learning can be contained within the family, kept private and discussed with members whom share common kin ties. The emotional support of friendship risks private consultation becoming public and has no biological status. Therefore, the family as a social and emotional provider is viewed as more important. The difference and diversity of families and friendship relations as pointed out in Shorter (1979, p.231-41) may provide insight into the importance of family dynamics. Shorter describes a variety of family and kin units, their origins and values placed on human contact. The research shows that despite having sociable human contact, preference is given to remaining close to family and kin, and protecting the family unit from external intrusion. Thus, providing the family with a direct sense of purpose and well-being for the individual, a place of sanctity and security when the outside world is no longer required or available. Our experiences of the world are subjective, we engage in both physical and emotional stimulation to suffice our needs. However, the main source for supply and demand of these needs is found in our value of our family and kin relationships. Family values are found in family traits, traditions and familiarity of its members and Family and Friends 5 its stability in a demographically changing social world. In this sense, friendships may come and go; however, family values will always remain, placing an emphasis on the importance of families. Where do families achieve their stability and security? The structural functionalism of families can assist in maintaining stability and security, through its ability to â€Å"provide individuals with the opportunity for  emotional support, companionship, sexual expression, reproduction and the socialisation of children†Ã¢â‚¬ ¦Ã¢â‚¬ They maintain social order and control through disciplining their children and other members† (Baker, 2001, p.73). The ability of families to maintain social and familial control provides members with a sense of self-control over ones life. A setting to which they can return to safe in the knowledge that emotional, physical and material guidance and support can be sought. Therefore, positioning the family as a place belonging and familiarity. Conclusion There appears to be little doubt that both family and friends play and important role in ones life. To measure to importance we cannot ignore the difference and diversity of both family and friendship relationships. For some the relationship of friends is extremely important, for others it is the relationship of the family. To assess why friendship relationships appear to be more important, it is essential to recognise the demographic changes that have occurred in the past and the rate at which changes occur in the present. Family dynamics now share a variety of different relationship structures such as, defacto, stepfamilies, same sex partners,  adoption and foster parenting. All of which have their own unique set of values, social and cultural traits. The apparent multitude of difference and diversity of both family and friendship arrangements, in an ever-changing world, may embrace the need for external relations outside the family. Friendship relationships can become symbolic of demographic changes, be non-compliant with family traditions and have the flexibility to endure future change. Thus, placing an importance on the need and value of friendship relationships.

Filipino Games Essay

Like any other country in the world, Philippines have many different games that are played as a past time, or simply for recreational purposes. Some games are more popular and more well-known than the others, but the three games that stuck out at me were Tubigan, Sungka, and Culliot. Tubigan, also known as Patintero, is played outdoors. The players are divided into two equal teams. Based on a coin toss, one team becomes the runners, and the other becomes the tagger. The object of the runner is to get through all the lines back and forth without being tagged. To set this game up, the ground is marked off in a 5 or 6 meter rectangle divided into four equal parts. The taggers stand 1, 2, 3, and 4 on the marked lines. Tagger number 1 can go anywhere to tag the runners. Taggers 2, 3, and 4 must have both feet on the marked lines, and can only tag the runner as they cross their lines or as they get near them. As soon as the runners cross line 4, he must return to line 2 and call out â€Å"Tubig! † scoring a point for his team. The runners must score a clean pass within 2 minutes; otherwise a turnover will be called. Sungka, known as mancala in Southern Asia, has been around in the Philippines for as long as anyone can remember. The sungka board is a small treasure – the older it is, the more precious, it sits on a side table or a top bench, waiting to be played. The sungka board is a shallow boat made of solid wood. The whole length of the boat is lined in seven small bowls carved in pairs, with two large deep bowls carved out at both ends (bahay) for captured â€Å"sigay†. The props needed for this game are pebbles, â€Å"sigay† or shells, or seeds. In each small pit are initially 7 â€Å"sigay. † Sungka is always played by two people. At each turn a player empties one of his small pits and then distributes its contents in a counterclockwise direction, one by one, into the following pits including his own store, but passing the opponents store. If the last stone falls into a non-empty small pit, its contents are lifted and distributed in another lap. If the last stone is dropped into the player’s own store, the player gets a bonus move. If the last stone is dropped into an empty pit, the move ends. If the move ends by dropping the last stone into one of your own small pits you capture the â€Å"sigay† in the opponent’s pit directly across the board and your own stone. The captured â€Å"sigay† are deposited in your store. However, if the opponent’s pit is empty, nothing is captured. The first move is played simultaneously. After that play is alternately. The first player to finish the first move may start the second move. However, in face-to-face play one player might start shortly after his opponent so that he could choose a response which would give him an advantage. There is no rule that actually could prevent such a tactic. So, in fact, the decision-making may be non-simultaneous. You must move if you can. If you can’t a player must pass until he can move again. The game ends when no â€Å"sigay† are left in the small pits. The player who captures most â€Å"sigay† wins the game. The game culliot is similar to the game of tug-of-war. Two or more players can play this. The purpose of this team is to pull the other team over the borderline. The equipment needed is a 15-meter long rope with a diameter of 3. 81 centimeters. Each team must have an equal number of players. The teams are placed five meters away from each other. Both ends of the rope should be tied on the waist of the last player while the others hold on to the rope. A piece of ribbon or handkerchief is tied onto the centerline of the rope. Upon the signal to start, each team pulls the other, attempting to pull the opposing team over the borderline, thus becoming the winner. In my opinion, the cultural aspect of these games teaches teamwork, skill, wit, as well as strength. Growing up, I have played all of the above games. I had no idea that they were Filipino games, except for sungka. I like these games because it brought my family and I closer together; my cousins and I especially. These games taught us how to work as a team, think about our decisions before we make a move, and wit.